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Shinde D, Bhat SK, Ganesh CB. The opioid peptide leucine enkephalin modulates hypothalamic-hypophysial axis in the cichlid fish Oreochromis mossambicus. Anim Reprod Sci 2024; 263:107451. [PMID: 38490066 DOI: 10.1016/j.anireprosci.2024.107451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/25/2024] [Accepted: 03/06/2024] [Indexed: 03/17/2024]
Abstract
In vertebrates, opioid peptides are thought to be involved in the regulation of reproduction; however, the significance of enkephalins in testicular function remains unclear. We examined the influence of δ-opioid receptor agonist leucine enkephalin (L-ENK) on the hypophysial-testicular axis of the cichlid fish Oreochromis mossambicus. Treatment with a low dose of L-ENK (60 µg) caused a significant increase in the numbers of primary and secondary spermatocytes and early and late spermatids, concomitant with intense immunolabelling of testicular androgen receptors, but did not significantly alter serum luteinizing hormone (LH) and 11-ketotestosterone (11-KT) levels compared to those of controls. Nevertheless, treatment with a high dose of L-ENK (200 µg) caused a significant reduction in the numbers of secondary spermatocytes as well as late spermatids associated with marginal immunolabelling of androgen receptors and significantly lower concentrations of serum 11-KT and LH compared to controls. In addition, the serum cortisol level was not affected in low-dose L-ENK-treated fish, but its level was significantly increased in the high-dose L-ENK-treated group. Together, these findings indicate that a low dose of L-ENK stimulates the germ cells at the meiosis stage and promotes further stages of spermatogenesis, whereas a high concentration of L-ENK inhibits spermatogenesis at the advanced stages. This effect appears to be mediated through the suppression of testicular steroidogenesis and the reduction of LH release in the pituitary gland of tilapia. The findings also suggest that elevated L-ENK levels in teleosts may exert their inhibitory influence on the hypophysial-testicular axis via glucocorticoids.
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Affiliation(s)
- Deepak Shinde
- Neuroendocrinology Research Laboratory, Department of Studies in Zoology, Karnatak University, Dharwad 580 003, India
| | - Shilpa K Bhat
- Neuroendocrinology Research Laboratory, Department of Studies in Zoology, Karnatak University, Dharwad 580 003, India
| | - C B Ganesh
- Neuroendocrinology Research Laboratory, Department of Studies in Zoology, Karnatak University, Dharwad 580 003, India.
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Wijesena HR, Nonneman DJ, Keel BN, Lents CA. Gene expression in the amygdala and hippocampus of cyclic and acyclic gilts. J Anim Sci 2022; 100:6497483. [PMID: 34984470 PMCID: PMC8801052 DOI: 10.1093/jas/skab372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/02/2022] [Indexed: 01/07/2023] Open
Abstract
Age at first estrus is the earliest phenotypic indicator of future reproductive success of gilts. Prebreeding anestrus is a major reason for reproductive failure leading to culling of replacement gilts. The two types of prebreeding anestrus are delay in attaining puberty (prepubertal anestrus, PPA) and silent ovulation (behavioral anestrus, BA). Neural tissues such as amygdala and hippocampus play a major role in regulating sexual behavior, social interactions, and receptivity to males. Differences in gene expression in the amygdala and hippocampus of gilts were analyzed in three comparisons: 1) PPA cases and cyclic controls at follicular phase of estrous cycle, 2) BA cases and cyclic controls at luteal phase of estrous cycle, and 3) gilts at different stages of the ovarian cycle (cyclic gilts at follicular phase and luteal phase of estrous cycle) to gain functional understanding of how these rarely studied tissues may differ between pubertal phenotypes and different stages of the estrous cycle of gilts. Differentially expressed genes (DEG) between PPA and BA cases and their respective cyclic controls were involved in neurological and behavioral disorders as well as nervous system functions that could directly or indirectly involved in development of behaviors related to estrus. The comparison between cyclic follicular and luteal phase control gilts identified the greatest number of DEG in the hippocampus and amygdala. These DEG were involved in adult neurogenesis and neural synapse (e.g., GABAergic, dopamine, cholinergic), suggesting that these tissues undergo structural changes and synaptic plasticity in gilts. This is the first report to demonstrate that the stage of estrous cycle is associated with dynamic changes in gene expression within porcine hippocampus and amygdala and indicates a role of gonadal steroids in regulating their biology.
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Affiliation(s)
- Hiruni R Wijesena
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, USA
| | - Dan J Nonneman
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, USA
| | - Brittney N Keel
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, USA
| | - Clay A Lents
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933-0166, USA,Corresponding author:
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Rossi GC, Bodnar RJ. Interactive Mechanisms of Supraspinal Sites of Opioid Analgesic Action: A Festschrift to Dr. Gavril W. Pasternak. Cell Mol Neurobiol 2021; 41:863-897. [PMID: 32970288 DOI: 10.1007/s10571-020-00961-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/03/2020] [Indexed: 12/30/2022]
Abstract
Almost a half century of research has elaborated the discoveries of the central mechanisms governing the analgesic responses of opiates, including their receptors, endogenous peptides, genes and their putative spinal and supraspinal sites of action. One of the central tenets of "gate-control theories of pain" was the activation of descending supraspinal sites by opiate drugs and opioid peptides thereby controlling further noxious input. This review in the Special Issue dedicated to the research of Dr. Gavril Pasternak indicates his contributions to the understanding of supraspinal mediation of opioid analgesic action within the context of the large body of work over this period. This review will examine (a) the relevant supraspinal sites mediating opioid analgesia, (b) the opioid receptor subtypes and opioid peptides involved, (c) supraspinal site analgesic interactions and their underlying neurophysiology, (d) molecular (particularly AS) tools identifying opioid receptor actions, and (e) relevant physiological variables affecting site-specific opioid analgesia. This review will build on classic initial studies, specify the contributions that Gavril Pasternak and his colleagues did in this specific area, and follow through with studies up to the present.
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Affiliation(s)
- Grace C Rossi
- Department of Psychology, C.W. Post College, Long Island University, Post Campus, Brookville, NY, USA.
| | - Richard J Bodnar
- Department of Psychology, Queens College of the City University of New York, Flushing, NY, USA
- CUNY Neuroscience Collaborative, Graduate Center, CUNY, New York, NY, USA
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Waters EM, Mazid S, Dodos M, Puri R, Janssen WG, Morrison JH, McEwen BS, Milner TA. Effects of estrogen and aging on synaptic morphology and distribution of phosphorylated Tyr1472 NR2B in the female rat hippocampus. Neurobiol Aging 2018; 73:200-210. [PMID: 30384123 DOI: 10.1016/j.neurobiolaging.2018.09.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/10/2018] [Accepted: 09/18/2018] [Indexed: 12/12/2022]
Abstract
Age and estrogens may impact the mobility of N-methyl-D-aspartate receptors (NMDARs) in hippocampal synapses. Here, we used serial section immunogold electron microscopy to examine whether phosphorylated tyrosine 1472 NR2B (pY1472), which is involved in the surface expression of NMDARs, is altered in the dorsal hippocampus of young (3-4 months old) and aged (∼24 months old) ovariectomized rats treated with 17β-estradiol or vehicle for 2 days. The number of gold particles labeling pY1472 was higher in presynaptic and postsynaptic compartments of aged rats with low estradiol (vehicle-treated) compared to other groups. In terminals, pY1472 levels were elevated in aged rats but reduced by estradiol treatment to levels seen in young rats. Conversely, the mitochondria number was lower in aged females but was restored to young levels by estradiol. In the postsynaptic density and dendritic spines, estradiol reduced pY1472 in young and aged rats. As phosphorylation at Y1472 blocks NR2B endocytosis, reduction of pY1472 by estradiol suggests another mechanism through which estrogen enhances synaptic plasticity by altering localization of NMDAR subunits within synapses.
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Affiliation(s)
- Elizabeth M Waters
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | - Sanoara Mazid
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | - Mariana Dodos
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Rishi Puri
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - William G Janssen
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - John H Morrison
- Department of Neurology, Center for Neuroscience, The California National Primate Research Center, UC Davis, Davis, CA, USA
| | - Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | - Teresa A Milner
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA; Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
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Kramer PR, Umorin M, Bellinger LL. Attenuation of myogenic orofacial nociception and mechanical hypersensitivity by viral mediated enkephalin overproduction in male and female rats. BMC Neurol 2015; 15:34. [PMID: 25885338 PMCID: PMC4369359 DOI: 10.1186/s12883-015-0285-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/25/2015] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Clinical studies have tested the use of an engineered herpes virus to treat pain. We hypothesized that subcutaneous injections of an engineered herpes virus that expresses enkephalin would attenuate orofacial nociception and hypersensitivity in male and female rats by a central mechanism. METHODS Herpes virus was injected subcutaneously around the mouth of male and female rats seventy-two hours before ligatures were placed on the masseter tendon, control treatment groups received either no virus or no ligature. Enkephalin expression was measured and von Frey filament testing and meal duration were utilized to measure mechanical hypersensitivity and the nociceptive response, respectively. Naloxone or naloxone methiodide was administered to rats injected with the enkephalin expressing virus to test if enkephalin was acting peripherally or centrally. RESULTS Ligature significantly lengthened meal duration and reduced the threshold to von Frey filaments for 18 days. Infection with the enkephalin transgene significantly decreased this response for at least 11 days but only in male rats. Virus injection significantly increased expression of enkephalin in the mental nerve that innervates the mouth region, the trigeminal ganglia and the trigeminal nucleus caudalis but no increase was observed in the masseter nerve after virus injection. Naloxone but not naloxone methiodide reversed the response to the enkephaline expressing virus. CONCLUSIONS The data suggests that sex should be a considered when using this virus and that viral transfection of the mental nerve with an enkephalin transgene can reduce nociception and hypersensitivity through a central mechanism.
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Affiliation(s)
- Phillip R Kramer
- Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, 3302 Gaston Avenue, Dallas, TX, 75246, USA.
| | - Mikhail Umorin
- Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, 3302 Gaston Avenue, Dallas, TX, 75246, USA.
| | - Larry L Bellinger
- Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, 3302 Gaston Avenue, Dallas, TX, 75246, USA.
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Georgescu M, Afonso VM, Graham MD, Pfaus JG. Glutamate release in the ventromedial hypothalamus of the female rat during copulation: modulation by estradiol. Horm Behav 2014; 65:119-26. [PMID: 24333845 DOI: 10.1016/j.yhbeh.2013.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 10/29/2013] [Accepted: 12/04/2013] [Indexed: 10/25/2022]
Abstract
Binding of glutamate or its ionotropic receptor agonists in the ventromedial hypothalamus (VMH) of female rats inhibits both appetitive and consummatory aspects of sexual behavior. Because vaginocervical stimulation activates glutamate neurons in the VMH, and administration of estradiol benzoate (EB) and progesterone (P) delays this effect, the present study examined the effects of hormonal priming on glutamate release within the VMH of female rats paired with sexually vigorous males. Ovariectomized, sexually experienced rats were implanted with guide cannula aimed at the ventrolateral VMH, through which microdialysis probes were inserted prior to testing. Females were assigned randomly to one of three hormone treatment conditions: EB+P, EB alone, or the oil vehicle. Testing was conducted over 5h, including a 120-min period of habituation to the testing chamber, a 60-min period of baseline sample collection, and a 120-min period during which a sexually vigorous male was introduced into the testing chamber. Dialysates were collected every 20min during the test and were analyzed for glutamate using HPLC. Females primed with oil had large and significant increases in glutamate release from baseline once the male was introduced to the chamber. Treatment with EB alone decreased glutamate release in response to male cues. Although treatment with EB+P did not differ significantly from EB alone, the degree of reduced glutamate release was less than with EB alone. These results indicate that priming with EB reduces glutamate transmission in the VMH in response to male cues. Taken together with our previous findings, estradiol blunts the activation of glutamate neurons in the VMH thus allowing female rats to copulate.
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Affiliation(s)
- M Georgescu
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, QC H4B 1R6, Canada
| | - V M Afonso
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, QC H4B 1R6, Canada
| | - M D Graham
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, QC H4B 1R6, Canada
| | - J G Pfaus
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, QC H4B 1R6, Canada.
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Amandusson Å, Blomqvist A. Estrogenic influences in pain processing. Front Neuroendocrinol 2013; 34:329-49. [PMID: 23817054 DOI: 10.1016/j.yfrne.2013.06.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 12/24/2022]
Abstract
Gonadal hormones not only play a pivotal role in reproductive behavior and sexual differentiation, they also contribute to thermoregulation, feeding, memory, neuronal survival, and the perception of somatosensory stimuli. Numerous studies on both animals and human subjects have also demonstrated the potential effects of gonadal hormones, such as estrogens, on pain transmission. These effects most likely involve multiple neuroanatomical circuits as well as diverse neurochemical systems and they therefore need to be evaluated specifically to determine the localization and intrinsic characteristics of the neurons engaged. The aim of this review is to summarize the morphological as well as biochemical evidence in support for gonadal hormone modulation of nociceptive processing, with particular focus on estrogens and spinal cord mechanisms.
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Affiliation(s)
- Åsa Amandusson
- Department of Clinical Neurophysiology, Uppsala University, 751 85 Uppsala, Sweden.
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8
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Simerly RB. Prodynorphin and proenkephalin gene expression in the anteroventral periventricular nucleus of the rat: Sexual differentiation and hormonal regulation. Mol Cell Neurosci 2012; 2:473-84. [PMID: 19912832 DOI: 10.1016/1044-7431(91)90014-f] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/1991] [Indexed: 11/16/2022] Open
Abstract
Opioid peptides are generally thought to exert hormone-dependent regulatory influences on gonadotropin secretion and the anteroventral periventricular nucleus (AVPv) has been shown to play a critical role in the neural control of this sexually dimorphic function. In the present study we used in situ hybridization to compare the numbers of proenkephalin (PENK) and prodynorphin (PDYN) mRNA-containing neurons in the AVPv of male and female rats and to evaluate the influence of circulating sex steroid hormones on the development and mature regulation of PENK and PDYN gene expression in these neurons. In agreement with earlier immunohistochemical observations, the number of PENK mRNA-containing neurons in the AVPv of male rats was found to be twice that of female animals. In contrast, the AVPv contains over four times the number of PDYN mRNA-containing cells in female rats, relative to intact males. Treatment of newborn female rats with testosterone increases the number of PENK mRNA-containing neurons in the AVPv, but decreases the number of PDYN mRNA-containing neurons in the AVPv compared with untreated females. Treatment of adult ovariectomized female rats with estradiol significantly increased PDYN mRNA levels in the AVPv; however, comparable changes in levels of PENK mRNA were not detected. In adult male rats, neither PDYN, nor PENK mRNA were significantly altered by orchidectomy or testosterone treatment. Thus, the maintenance of enkephalinergic neurons and the loss of hormone-sensitive dynorphin-containing neurons in the AVPv may represent important developmental influences of neonatal androgens on the sexually differentiated neural circuitry controlling gonadotropin secretion.
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Affiliation(s)
- R B Simerly
- Division of Neuroscience, Oregon Regional Primate Research Center, Beaverton, Oregon 97006, USA
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9
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Stevenson TJ, Calabrese MD, Ball GF. Variation in enkephalin immunoreactivity in the social behavior network and song control system of male European starlings (Sturnus vulgaris) is dependent on breeding state and gonadal condition. J Chem Neuroanat 2012; 43:87-95. [DOI: 10.1016/j.jchemneu.2011.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 11/12/2011] [Accepted: 12/14/2011] [Indexed: 10/14/2022]
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10
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Waters EM, Yildirim M, Janssen WGM, Lou WYW, McEwen BS, Morrison JH, Milner TA. Estrogen and aging affect the synaptic distribution of estrogen receptor β-immunoreactivity in the CA1 region of female rat hippocampus. Brain Res 2011; 1379:86-97. [PMID: 20875808 PMCID: PMC3046233 DOI: 10.1016/j.brainres.2010.09.069] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 09/17/2010] [Accepted: 09/17/2010] [Indexed: 11/29/2022]
Abstract
Estradiol (E) mediates increased synaptogenesis in the hippocampal CA1 stratum radiatum (sr) and enhances memory in young and some aged female rats, depending on dose and age. Young female rats express more estrogen receptor α (ERα) immunolabeling in CA1sr spine synapse complexes than aged rats and ERα regulation is E sensitive in young but not aged rats. The current study examined whether estrogen receptor β (ERβ) expression in spine synapse complexes may be altered by age or E treatment. Young (3-4 months) and aged (22-23 months) female rats were ovariectomized 7 days prior to implantation of silastic capsules containing either vehicle (cholesterol) or E (10% in cholesterol) for 2 days. ERβ immunoreactivity (ir) in CA1sr was quantitatively analyzed using post-embedding electron microscopy. ERβ-ir was more prominent post-synaptically than pre-synaptically and both age and E treatment affected its synaptic distribution. While age decreased the spine synaptic complex localization of ERβ-ir (i.e., within 60 nm of the pre- and post-synaptic membranes), E treatment increased synaptic ERβ in both young and aged rats. In addition, the E treatment, but not age, increased dendritic shaft labeling. This data demonstrates that like ERα the levels of ERβ-ir decrease in CA1 axospinous synapses with age, however, unlike ERα the levels of ERβ-ir increase in these synapses in both young and aged rats in response to E. This suggests that synaptic ERβ may be a more responsive target to E, particularly in aged females.
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Affiliation(s)
- Elizabeth M Waters
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065, USA.
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Williams TJ, Mitterling KL, Thompson LI, Torres-Reveron A, Waters EM, McEwen BS, Gore AC, Milner TA. Age- and hormone-regulation of opioid peptides and synaptic proteins in the rat dorsal hippocampal formation. Brain Res 2010; 1379:71-85. [PMID: 20828542 DOI: 10.1016/j.brainres.2010.08.103] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 08/13/2010] [Accepted: 08/31/2010] [Indexed: 02/05/2023]
Abstract
Circulating estrogen levels and hippocampal-dependent cognitive functions decline with aging. Moreover, the responses of hippocampal synaptic structure to estrogens differ between aged and young rats. We recently reported that estrogens increase levels of post-synaptic proteins, including PSD-95, and opioid peptides leu-enkephalin and dynorphin in the hippocampus of young animals. However, the influence of ovarian hormones on synaptic protein and opioid peptide levels in the aging hippocampus is understudied. Here, young (3- to 5-month-old), middle-aged (9- to 12-month-old), and aged (about 22-month-old) female rats were ovariectomized and then, 4 weeks later, subcutaneously implanted with a silastic capsule containing vehicle or 17β-estradiol. After 48 h, rats were subcutaneously injected with progesterone or vehicle and sacrificed 1 day later. Coronal sections through the dorsal hippocampus were processed for quantitative peroxidase immunohistochemistry of leu-enkephalin, dynorphin, synaptophysin, and PSD-95. With age, females showed opposing changes in leu-enkephalin and dynorphin levels in the mossy fiber pathway, particularly within the hilus, and regionally specific changes in synaptic protein levels. 17β-estradiol, with or without progesterone, altered leu-enkephalin levels in the dentate gyrus and synaptophysin levels in the CA1 of young but not middle-aged or aged females. Additionally, 17β-estradiol decreased synaptophysin levels in the CA3 of middle-aged females. Our results support and extend previous findings indicating 17β-estradiol modulation of hippocampal opioid peptides and synaptic proteins while demonstrating regional and age-specific effects. Moreover, they lend credence to the "window of opportunity" hypothesis during which hormone replacement can modulate hippocampal structure and circuitry to improve cognitive outcomes.
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Affiliation(s)
- Tanya J Williams
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA.
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12
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Yildirim M, Janssen WGM, Lou WYW, Akama KT, McEwen BS, Milner TA, Morrison JH. Effects of estrogen and aging on the synaptic distribution of phosphorylated Akt-immunoreactivity in the CA1 region of the female rat hippocampus. Brain Res 2010; 1379:98-108. [PMID: 20709039 DOI: 10.1016/j.brainres.2010.07.053] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 07/15/2010] [Accepted: 07/16/2010] [Indexed: 02/08/2023]
Abstract
The estrogen 17β-estradiol (E) increases the axospinous synaptic density and plasticity in the hippocampal CA1 region of young female rats but fails to do so in aged female rats. This E stimulus on synaptic plasticity is associated with the phosphorylation-dependent activation of Akt kinase. Our previous findings demonstrated that increased estrogen levels subsequently increase phosphorylated Akt (pAkt)-immunoreactivity (-IR) within the dendritic shafts and spines of pyramidal neurons in young female rats. Therefore, because Akt can promote cell survival and growth, we tested the hypothesis that the less plastic synapses of aged female rats would contain less E-stimulated pAkt-IR. Here, young (3-4 months) and aged (22-23 months) female rats were ovariectomized 7 days prior to a 48-h administration of either vehicle or E. The pAkt-IR synaptic distribution was then analyzed using post-embedding electron microscopy. In both young and aged rats, pAkt-IR was found in dendritic spines and terminals, and pAkt-IR was particularly abundant at the post-synaptic density. Quantitative analyses revealed that the percentage of pAkt-labeled synapses was significantly greater in young rats compared to aged rats. Nonetheless, E treatment significantly increased pAkt-IR in pre- and post-synaptic profiles of both young and aged rats, although the stimulus in young rats was notably more widespread. These data support the evidence that hormone-activated signaling associated with cell growth and survival is diminished in the aged brain. However, the observation that E can still increase pAkt-IR in aged synapses presents this signaling component as a candidate target for hormone replacement therapies.
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Affiliation(s)
- Murat Yildirim
- Fishberg Department of Neuroscience, Mount Sinai School of Medicine, New York, NY 10029, USA
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Georgescu M, Sabongui C, Del Corpo A, Marsan L, Pfaus JG. Vaginocervical stimulation induces Fos in glutamate neurons in the ventromedial hypothalamus: attenuation by estrogen and progesterone. Horm Behav 2009; 56:450-6. [PMID: 19665463 DOI: 10.1016/j.yhbeh.2009.07.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 07/30/2009] [Accepted: 07/30/2009] [Indexed: 10/20/2022]
Abstract
Vaginocervical stimulation (VCS) induces the immediate-early gene product Fos in the ventromedial hypothalamus (VMH) of female rats. However, this induction is lower in ovariectomized rats that receive estradiol benzoate (EB) and progesterone (P) relative to an oil vehicle. We have observed that a substantial proportion of cells activated in the VMH by VCS stain for glutamate, and infusions of glutamate or its selective receptor agonists to the VMH inhibit both appetitive and consummatory sexual behaviors in females. This raises the possibility that VCS activates an inhibitory glutamate system in the VMH, and that ovarian steroids blunt the activation, although it is not known whether EB or P, alone or in combination, lead to this effect. The present experiment examined the ability of VCS to induce Fos in glutamate neurons in the VMH of ovariectomized rats under 4 hormonal regimens: oil, EB alone, P alone, or EB+P, following 1 or 50 distributed VCSs administered with a lubricated glass rod over the course of 1 h. Treatment with EB or P alone significantly reduced the number of glutamate neurons activated by 1 VCS, with P being more effective than EB. Treatment with EB+P also produced a significant reduction, but not to the extent of EB or P alone. Although EB and P work in synergy to activate sexual behavior in female rats, actions of EB or P alone are sufficient to blunt the ability of VCS to activate glutamate neurons in the VMH. It thus appears that ovarian steroids may "disinhibit" sexual responding, in part, by dampening the ability of VCS to activate glutamate neurons in the VMH. In turn, this may allow females to receive a sufficient number of intromissions for the activation of sexual reward and the facilitation of pregnancy.
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Affiliation(s)
- Michaela Georgescu
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, QC, Canada
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14
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Micevych P, Dominguez R. Membrane estradiol signaling in the brain. Front Neuroendocrinol 2009; 30:315-27. [PMID: 19416735 PMCID: PMC2720427 DOI: 10.1016/j.yfrne.2009.04.011] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 04/22/2009] [Accepted: 04/23/2009] [Indexed: 12/16/2022]
Abstract
While the physiology of membrane-initiated estradiol signaling in the nervous system has remained elusive, a great deal of progress has been made toward understanding the activation of cell signaling. Membrane-initiated estradiol signaling activates G proteins and their downstream cascades, but the identity of membrane receptors and the proximal signaling mechanism(s) have been more difficult to elucidate. Mounting evidence suggests that classical intracellular estrogen receptor-alpha (ERalpha) and ERbeta are trafficked to the membrane to mediate estradiol cell signaling. Moreover, an interaction of membrane ERalpha and ERbeta with metabotropic glutamate receptors has been identified that explains the pleomorphic actions of membrane-initiated estradiol signaling. This review focuses on the mechanism of actions initiated by membrane estradiol receptors and discusses the role of scaffold proteins and signaling cascades involved in the regulation of nociception, sexual receptivity and the synthesis of neuroprogesterone, an important component in the central nervous system signaling.
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Affiliation(s)
- Paul Micevych
- Department of Neurobiology and the Laboratory of Neuroendocrinology David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1763, USA.
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15
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16
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Ovarian steroids modulate leu-enkephalin levels and target leu-enkephalinergic profiles in the female hippocampal mossy fiber pathway. Brain Res 2008; 1232:70-84. [PMID: 18691558 DOI: 10.1016/j.brainres.2008.07.058] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 07/11/2008] [Accepted: 07/15/2008] [Indexed: 02/05/2023]
Abstract
In the hippocampal formation (HF), the enkephalin opioids and estrogen are each known to modulate learning and cognitive performance relevant to drug abuse. Within the HF, leu-enkephalin (LENK) is most prominent in the mossy fiber (MF) pathway formed by the axons of dentate gyrus (DG) granule cells. To examine the influence of ovarian steroids on MF pathway LENK levels, we used quantitative light microscopic immunocytochemistry to evaluate LENK levels in normal cycling rats and in estrogen-treated ovariectomized rats. Rats in estrus had increased levels of LENK-immunoreactivity (ir) in the DG hilus compared to rats in diestrus or proestrus. Rats in estrus and proestrus had higher levels of LENK-ir in CA3a-c compared to rats in diestrus. Ovariectomized (OVX) rats 24 h (but not 6 or 72 h) after estradiol benzoate (EB; 10 microg) administration had increased LENK-ir in the DG hilus and CA3c. Electron microscopy showed a larger proportion of LENK-labeled small terminals and axons in the DG hilus compared to CA3 which may have contributed to region-specific changes in LENK-ir densities. Next we evaluated the subcellular relationships of estrogen receptor (ER) alpha, ERbeta and progestin receptor (PR) with LENK-labeled MF pathway profiles using dual-labeling electron microscopy. ERbeta-ir colocalized in some LENK-labeled MF terminals and smaller terminals while PR-ir was mostly in CA3 axons, some of which also showed colocalization with LENK. ERalpha-ir was in dendritic spines, but no colocalization with LENK-labeled profiles was observed. The present studies indicate that estrogen can modulate LENK in subregions of the MF pathway in a dose-and time-dependent manner. These effects might be triggered by direct activation of ERbeta or PR in LENK-containing terminals.
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17
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Yildirim M, Janssen WGM, Tabori NE, Adams MM, Yuen GS, Akama KT, McEwen BS, Milner TA, Morrison JH. Estrogen and aging affect synaptic distribution of phosphorylated LIM kinase (pLIMK) in CA1 region of female rat hippocampus. Neuroscience 2008; 152:360-70. [PMID: 18294775 DOI: 10.1016/j.neuroscience.2008.01.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 01/03/2008] [Accepted: 01/10/2008] [Indexed: 01/03/2023]
Abstract
17beta-Estradiol (E) increases axospinous synapse density in the hippocampal CA1 region of young female rats, but not in aged rats. This may be linked to age-related alterations in signaling pathways activated by synaptic estrogen receptor alpha (ER-alpha) that potentially regulate spine formation, such as LIM-kinase (LIMK), an actin depolymerizing factor/cofilin kinase. We hypothesized that, as with ER-alpha, phospho-LIM-kinase (pLIMK) may be less abundant or responsive to E in CA1 synapses of aged female rats. To address this, cellular and subcellular distribution of pLIMK-immunoreactivity (IR) in CA1 was analyzed by light and electron microscopy in young and aged female rats that were ovariectomized and treated with either vehicle or E. pLIMK-IR was found primarily in perikarya within the pyramidal cell layer and dendritic shafts and spines in stratum radiatum (SR). While pLIMK-IR was occasionally present in terminals, post-embedding quantitative analysis of SR showed that pLIMK had a predominant post-synaptic localization and was preferentially localized within the postsynaptic density (PSD). The percentage of pLIMK-labeled synapses increased (30%) with E treatment (P<0.02) in young animals, and decreased (43%) with age (P<0.002) regardless of treatment. The pattern of distribution of pLIMK-IR within dendritic spines and synapses was unaffected by age or E treatment, with the exception of an E-induced increase in the non-synaptic core of spines in young females. These data suggest that age-related synaptic alterations similar to those seen with ER-alpha occur with signaling molecules such as pLIMK, and support the hypothesis that age-related failure of E treatment to increase synapse number in CA1 may be due to changes in the molecular profile of axospinous synapses with respect to signaling pathways linked to formation of additional spines and synapses in response to E.
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Affiliation(s)
- M Yildirim
- Department of Pharmacology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
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18
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Pfaff DW, Brooks PJ, Funabashi T, Pfaus JG, Mobbs CV. Gene memory in neuroendocrine and behavioural systems. CIBA FOUNDATION SYMPOSIUM 2007; 168:165-83; discussion 183-6. [PMID: 1425024 DOI: 10.1002/9780470514283.ch11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Several examples of sex steroid hormone actions on rat brain and behaviour show that initial hormone exposures may be followed by enduring neuronal alterations, apparent long after the hormone itself has disappeared. Precedents from non-neuronal systems led to the concept of 'gene memory'. We are studying genomic structural alterations in rat hypothalamic neurons to account for these effects. The preproenkephalin gene is turned on by oestradiol in rat brain neurons in a tissue-specific and genetic sex-specific manner. Levels of preproenkephalin mRNA in the ventromedial hypothalamus correlate tightly with oestradiol-dependent reproductive behaviour. Our results indicate a tissue-specific pattern of DNA methylation in the enkephalin promoter. Putative binding sites for several transcription factors have been described in the preproenkephalin gene promoter; a role for some of these factors in regulating expression of the gene has been demonstrated.
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Affiliation(s)
- D W Pfaff
- Laboratory of Neurobiology and Behavior, Rockefeller University, NY 10021-6399
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19
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Priest CA, Pfaff DW. Actions of sex steroids on behaviours beyond reproductive reflexes. CIBA FOUNDATION SYMPOSIUM 2007; 191:74-84; discussion 84-9. [PMID: 8582207 DOI: 10.1002/9780470514757.ch5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The actions of sex steroids in the brain have been shown, from molecular to systems levels, to control reproductive behaviour in a wide range of vertebrates. It has become increasingly clear that gonadal steroid hormones have regulatory functions which extend far beyond the direct coordination of an animal's physiological state and its display of sexual behaviour. While some of these actions may include changes in mood or other behavioural measures, such as exploration or excitability, sex steroid hormones also influence neural plasticity, neuronal activity and, possibly, learning and memory, as reflected by long-term potentiation or age-related deficits. Here we describe two systems that have been used to explore the non-reproductive roles of gonadal steroid hormones. The first of these is to examine the oestrogen-sensitive opioid peptide gene expression in the hypothalamus. Currently, we are attempting to identify the types of behaviour which may be altered consequent to the oestrogenic induction of the preproenkephalin gene. The second approach involves studying the effects of progesterone at the neuronal cell membrane and characterizing the metabolites of progesterone which have benzodiazepine-like actions in the brain. A number of studies suggest that this may provide an alternative mechanism through which progesterone can influence mood or behaviour.
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Affiliation(s)
- C A Priest
- Neurobiology and Behavior Laboratory, Rockefeller University, New York, NY 10021, USA
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20
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Maerkel K, Durrer S, Henseler M, Schlumpf M, Lichtensteiger W. Sexually dimorphic gene regulation in brain as a target for endocrine disrupters: developmental exposure of rats to 4-methylbenzylidene camphor. Toxicol Appl Pharmacol 2006; 218:152-65. [PMID: 17188730 DOI: 10.1016/j.taap.2006.10.026] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Revised: 10/02/2006] [Accepted: 10/29/2006] [Indexed: 11/21/2022]
Abstract
The developing neuroendocrine brain represents a potential target for endocrine active chemicals. The UV filter 4-methylbenzylidene camphor (4-MBC) exhibits estrogenic activity, but also interferes with the thyroid axis. We investigated effects of pre- and postnatal exposure to 4-MBC in the same rat offspring at brain and reproductive organ levels. 4-MBC (7, 24, 47 mg/kg/day) was administered in chow to the parent generation before mating, during gestation and lactation, and to the offspring until adulthood. mRNA of estrogen target genes involved in control of sexual behavior and gonadal functions was measured by real-time RT-PCR in ventromedial hypothalamic nucleus (VMH) and medial preoptic area (MPO) of adult offspring. 4-MBC exposure affected mRNA levels of ER alpha, progesterone receptor (PR), preproenkephalin (PPE) and insulin-like growth factor-I (IGF-I) in a sex- and region-specific manner. In order to assess possible changes in sensitivity of target genes to estrogens, offspring were gonadectomized on day 70, injected with estradiol (E2, 10 or 50 microg/kg s.c.) or vehicle on day 84, and sacrificed 6 h later. The acute induction of PR mRNA, and repression (at 6 h) of PPE mRNA by E2 was enhanced by 4-MBC in male and female VMH and female MPO, whereas male MPO exhibited reduced responsiveness of both genes. Steroid receptor coactivator SRC-1 mRNA levels were increased in female VMH and MPO. The data indicate profound sex- and region-specific alterations in the regulation of estrogen target genes at brain level. Effect patterns in baseline and E2-induced gene expression differ from those in uterus and prostate.
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Affiliation(s)
- Kirsten Maerkel
- Institute of Pharmacology and Toxicology and GREEN Tox, University of Zurich, CH-8057 Zurich, Switzerland
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21
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Walf AA, Frye CA. A review and update of mechanisms of estrogen in the hippocampus and amygdala for anxiety and depression behavior. Neuropsychopharmacology 2006; 31:1097-111. [PMID: 16554740 PMCID: PMC3624621 DOI: 10.1038/sj.npp.1301067] [Citation(s) in RCA: 346] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Estrogen (E2) has many effects in the central nervous system, including effects on anxiety and depression behavior. This review will address effects of E2 on behaviors related to anxiety and depression in women and animal models and include recent findings from our laboratory related to this topic. E2's antianxiety and antidepressant-like effects may depend upon many factors, including the regimen of E2 utilized and interactions with the hypothalamic-pituitary-adrenal axis. Brain targets for E2's effects on anxiety and depression include the hippocampus and amygdala. Administration of E2, compared to vehicle, subcutaneously or to the hippocampus or amygdala of ovariectomized rats decreases anxiety and depressive behavior. Intracellular estrogen receptors (ERs) may be important for E2's anxiolytic and antidepressant-like effects. Administration of an ER antagonist to the hippocampus, but not amygdala, increases anxiety and depression behavior of naturally receptive female rats. Studies utilizing ER knockout mice or selective ER modulators suggest that ER-mediated effects of E2 on anxiety and depressive behavior may require ERbeta. In addition, the behavioral effects of E2 may involve membrane actions and/or changes in cell cycle processes involved in energy expenditure. Elucidating the mechanisms by which E2 affects anxiety and depression is important in order to enhance its therapeutic potential. It is particularly important to investigate the putative receptor mechanisms and brain targets for E2 to determine whether mood-enhancing effects of E2 can occur without deleterious proliferative effects in reproductive tissues.
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Affiliation(s)
- Alicia A Walf
- Department of Psychology, The University at Albany-SUNY, Albany, NY, USA
| | - Cheryl A Frye
- Department of Psychology, The University at Albany-SUNY, Albany, NY, USA
- Department of Biological Sciences, The University at Albany-SUNY, Albany, NY, USA
- Center for Neuroscience Research, The University at Albany-SUNY, Albany, NY, USA
- Center for Life Science Research, The University at Albany-SUNY, Albany, NY, USA
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22
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Franklin SO, Jimenez R. Increases in preproenkephalin mRNA levels in the Syrian hamster: The influence of glucocorticoids is dependent on age and tissue. Brain Res 2006; 1086:65-75. [PMID: 16597437 DOI: 10.1016/j.brainres.2006.02.077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 02/19/2006] [Accepted: 02/21/2006] [Indexed: 12/22/2022]
Abstract
In adult hamsters, basal proenkephalin (Penk) gene expression in adrenals is independent of glucocorticoids and glucocorticoid receptor blockade, by RU 486, increases striatal preproenkephalin (PPenk) mRNA levels. However, glucocorticoids maintain both basal and induced Penk gene expression in rat adrenal (medulla) and striatum. This suggests species and tissue-specific differences in Penk gene regulation. Since studies show temporal coordination in Penk gene expression in developing hamster adrenal and striatum, we tested the hypothesis that increasing PPenk mRNA levels are dependent, while basal levels are independent of glucocorticoids in developing hamsters. To facilitate this study, we examined the influence of glucocorticoids on the temporal increases in developing hamster PPenk mRNA observed in adrenals between postnatal days 0 and 4 and in striatum between postnatal days 12 and 48. PPenk mRNA levels were determined in hamster pups after treatment with increasing doses of metyrapone (an 11beta hydroxylase inhibitor) or with the glucocorticoid receptor antagonist RU 486 +/- metyrapone between postnatal days 2 and 4. Levels were also determined 36 days after hypophysectomy at age 16-17 days. Although plasma glucocorticoid levels and/or the influence from glucocorticoids were reduced, only developmental increases in PPenk mRNA are influenced by glucocorticoids in hamster adrenals, while basal adrenal mRNA levels are unchanged. However, pituitary influence on striatal PPenk mRNA levels appears complex and may involve steroid and/or non-steroid factors. These results suggest that glucocorticoids regulate hamster Penk gene expression via a mechanism that varies with age and tissue and functions during the induction of the Penk gene and not to maintain basal gene expression. Possible mechanisms and species variation are discussed.
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Affiliation(s)
- Steven O Franklin
- Program in the Neuroscience of Drug Abuse, Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, 700 George Street, Durham, 27707, USA.
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23
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Slamberová R, Hnatczuk OC, Vathy I. Expression of proopiomelanocortin and proenkephalin mRNA in sexually dimorphic brain regions are altered in adult male and female rats treated prenatally with morphine. ACTA ACUST UNITED AC 2005; 63:399-408. [PMID: 15140157 DOI: 10.1111/j.1399-3011.2004.00134.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The present study demonstrates that prenatal morphine exposure on gestation days 11-18 differentially alters proopiomelanocortin (POMC) and proenkephalin (pENK) mRNA in the hypothalamus and limbic system of adult male and female rats. In adult, prenatally morphine-exposed male rats POMC mRNA levels are decreased in the arcuate nucleus of the hypothalamus (ARC), while the pENK mRNA levels are increased in the paraventricular nucleus of the hypothalamus (PVN) and in the ventrolateral subdivision of the ventromedial nucleus of the hypothalamus (VMH), specifically in the ventrolateral subdivision of the VMH. In adult, prenatally morphine-exposed female rats, POMC mRNA levels in the ARC are increased in ovariectomized (OVX) but not in OVX, estradiol benzoate- (EB) or EB- and progesterone- (P) treated females. In contrast, pENK mRNA levels are decreased in the VMH of morphine-exposed, OVX females and increased in EB-treated females. Further, prenatal morphine exposure decreases pENK mRNA in the ARC and increases it in the medial pre-optic area independently of female gonadal hormones. Finally, POMC mRNA levels are increased in the ARC of saline-exposed, EB- or EB- and P-treated females but not in OVX females. Thus, the present study suggests that prenatal morphine exposure sex and brain region specifically alters the level of POMC and pENK mRNA.
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Affiliation(s)
- R Slamberová
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, 1300 Morris Park Ave, Ull. 111, Bronx, NY 10461, USA
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25
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Charlier TD, Balthazart J. Modulation of Hormonal Signaling in the Brain by Steroid Receptor Coactivators. Rev Neurosci 2005; 16:339-57. [PMID: 16519010 DOI: 10.1515/revneuro.2005.16.4.339] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Nuclear receptors, such as estrogen, glucocorticoid or thyroid hormone receptors, have been shown to play a critical role in brain development and physiology. The activity of these receptors is modulated by the interaction with several proteins and, in particular, coactivators are required to enhance their transcriptional activity. The steroid receptor coactivators (SRC-1, -2 and -3) are currently the best characterized coactivators and we review here the current knowledge on the distribution and function of these proteins in the brain. Knock-out models and antisense techniques have demonstrated the requirement for SRC-1 and -2 in the brain, focusing mainly on steroid and thyroid hormone-dependent development and behavior. The precise function of SRC-3 in the brain is currently unknown but its presence throughout the brain suggests an important function. Although the molecular biology of SRCs is relatively well known, the in vivo control of their expression, post-translational modifications and time- and cell-specific interactions with the different nuclear receptors remain elusive. A complete understanding of hormone action on brain and behavior will not be attained until a better knowledge of coactivator physiology is achieved.
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Affiliation(s)
- Thierry D Charlier
- University of Liège, Center for Cellular and Molecular Neurobiology, Research Group in Behavioral Neuroendocrinology, Belgium.
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26
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Schlumpf M, Schmid P, Durrer S, Conscience M, Maerkel K, Henseler M, Gruetter M, Herzog I, Reolon S, Ceccatelli R, Faass O, Stutz E, Jarry H, Wuttke W, Lichtensteiger W. Endocrine activity and developmental toxicity of cosmetic UV filters--an update. Toxicology 2004; 205:113-22. [PMID: 15458796 DOI: 10.1016/j.tox.2004.06.043] [Citation(s) in RCA: 274] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
UV filters represent a new class of endocrine active chemicals. In vitro, 8/9 chemicals showed estrogenic (MCF-7 cells), and 2/9 antiandrogenic activity (MDA-kb2 cells). Six/nine filters (benzophenone (Bp)-1, Bp-2, Bp-3, 3-benzylidene camphor (3-BC), 4-methylbenzylidene camphor (4-MBC), octyl-methoxycinnamate (OMC)) increased uterine weight in immature rats. 3-Benzylidene camphor and 4-MBC displaced 16alpha125I-estradiol from human estrogen receptor (ER)beta, not ERalpha. Developmental toxicity of 4-MBC (0.7-47 mg/kg body weight/day) and 3-BC (0.24-7 mg/kg), administered in chow was investigated in Long Evans (LE) rats. Weight gain of pregnant rats was reduced only by 3-BC, early postnatal survival rate and thymus weight by both compounds at higher doses. 4-Methylbenzylidene camphor and 3-BC delayed male puberty, and dose-dependently affected reproductive organ weights of adult male and female F1 offspring, with partly different effect patterns. Thyroid weight was increased by higher 4-MBC doses. Tissue-specific changes in mRNA levels of estrogen-regulated genes in prostate, uterus and brain regions, determined by real-time PCR, and in their response to acute estradiol challenge in adult gonadectomized offspring were observed. Lowest effective doses were 0.24 mg/kg/day for 3-BC and 7 mg/kg/day for 4-MBC. Fat tissue levels at 7 mg/kg 4-MBC (GC-MS) approached the range of UV filters in fish (Nagtegaal et al., 1997; Balmer et al., 2004).
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Affiliation(s)
- Margret Schlumpf
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
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27
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Erskine MS, Lehmann ML, Cameron NM, Polston EK. Co-regulation of female sexual behavior and pregnancy induction: an exploratory synthesis. Behav Brain Res 2004; 153:295-315. [PMID: 15265625 DOI: 10.1016/j.bbr.2004.01.026] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2003] [Revised: 12/20/2003] [Accepted: 01/11/2004] [Indexed: 11/20/2022]
Abstract
This paper will review both new and old data that address the question of whether brain mechanisms involved in reproductive function act in a coordinated way to control female sexual behavior and the induction of pregnancy/pseudopregnancy (P/PSP) by vaginocervical stimulation. Although it is clear that female sexual behavior, including pacing behavior, is important for induction of P/PSP, there has been no concerted effort to examine whether or how common mechanisms may control both functions. Because initiation of P/PSP requires that the female receive vaginocervical stimulation, central mechanisms controlling P/PSP may be modulated by or interactive with those that control female sexual behavior. This paper presents a synthesis of the literature and recent data from our lab for the purpose of examining whether there are interactions between behavioral and neuroendocrine mechanisms which reciprocally influence both reproductive functions.
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Affiliation(s)
- Mary S Erskine
- Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA.
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28
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Yoo JH, Lee SY, Loh HH, Ho IK, Jang CG. Altered emotional behaviors and the expression of 5-HT1A and M1 muscarinic receptors in ?-opioid receptor knockout mice. Synapse 2004; 54:72-82. [PMID: 15352132 DOI: 10.1002/syn.20067] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Anxiety and depression alterations have been reported in micro-opioid receptor knockout mice after exon 2 disruption. However, emotional behaviors, such as novelty and emergence responses have not been reported in micro-opioid receptor knockout mice due to the disruptions of exon 2 and 3. Here, we report that mu-opioid receptor knockout mice, with deletion of exon 2 and 3, display significant emotional behavior changes; they showed less anxiety in the elevated plus maze and emergence tests, reduced response to novel stimuli in the novelty test, and less depressive-like behavior in the forced-swim test. Analysis of the compensatory mechanism in mu-opioid receptor knockout mice revealed that the M1 mRNA levels were reduced in the cortex, caudate putamen, nucleus accumbens, and hippocampus, and that M1 receptor levels were reduced in the nucleus accumbens, CA1, and the dentate gyrus of the hippocampus, versus the wild-type. However, 5-HT1A receptor levels were significantly elevated in the cerebral cortex and in the hypothalamus of mu-opioid receptor knockout mice versus the wild-type. These aberrant emotional behavioral phenotypes are possibly related to M1 and 5-HT1A receptor alterations in the micro-opioid receptor knockout mice. Overall, our study suggests that micro-opioid receptor may play a role in the modification of emotional responses to novelty, anxiety, and depression.
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MESH Headings
- 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacokinetics
- Analysis of Variance
- Animals
- Behavior, Animal
- Brain/anatomy & histology
- Brain/diagnostic imaging
- Emotions/physiology
- Exploratory Behavior/physiology
- Gene Expression Regulation/physiology
- Immobilization
- In Situ Hybridization/methods
- Maze Learning/physiology
- Mice
- Mice, Knockout
- Muscarinic Antagonists/pharmacokinetics
- Pirenzepine/pharmacokinetics
- RNA, Messenger/metabolism
- Radioligand Assay/methods
- Radionuclide Imaging
- Reaction Time/genetics
- Receptor, Muscarinic M1/genetics
- Receptor, Muscarinic M1/metabolism
- Receptor, Serotonin, 5-HT1A/genetics
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptors, Opioid, mu/deficiency
- Receptors, Opioid, mu/genetics
- Serotonin Receptor Agonists/pharmacokinetics
- Swimming/physiology
- Time Factors
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Affiliation(s)
- Ji-Hoon Yoo
- Department of Pharmacology, College of Pharmacy, Sungkyunkwan University, Suwon 440-746, Republic of Korea
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29
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Adams MM, Fink SE, Janssen WGM, Shah RA, Morrison JH. Estrogen modulates synapticN-methyl-D-aspartate receptor subunit distribution in the aged hippocampus. J Comp Neurol 2004; 474:419-26. [PMID: 15174084 DOI: 10.1002/cne.20148] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Estrogen interacts with N-methyl-D-aspartate (NMDA) receptors to regulate multiple aspects of morphological and functional plasticity. In hippocampus, estrogen increases both dendritic spine density and synapse number, and NMDA antagonists block these effects. Thus, estrogen-mediated hippocampal plasticity may be of particular importance in the context of age-related changes in endocrine status and cognitive performance. NR1 levels per synapse are increased in CA1 by estrogen in aged rats but not young rats, although no information is available on estrogen-induced synaptic alterations in other NMDA receptor subunits that might impact function. Therefore, the present study was designed to investigate the effect of estrogen on the synaptic and subsynaptic distributions of the NMDA receptor subunits, NR2A and NR2B in CA1 pyramidal cells, within the context of aging. Our results demonstrated that the overall synaptic levels of NR2A and NR2B are similar in young and aged female rats, regardless of estrogen treatment. However, in the aged CA1, estrogen restores NR2B levels back to young levels in the lateral portions of the active synaptic zone. Thus, estrogen may impact the mobility of NMDA receptors across the synapse and, in the process, restore a more youthful synaptic profile. These findings have important implications for the mechanism of estrogen-induced alterations in NMDA receptor-mediated processes, particularly in the context of aging.
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Affiliation(s)
- Michelle M Adams
- Department of Geriatrics and Adult Development, Mount Sinai School of Medicine, New York, New York 10029, USA
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30
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Corchero J, Fuentes JA, Manzanares J. Gender differences in proenkephalin gene expression response to delta9-tetrahydrocannabinol in the hypothalamus of the rat. J Psychopharmacol 2002; 16:283-9. [PMID: 12503826 DOI: 10.1177/026988110201600401] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Chronic exposure to delta9-tetrahydrocannabinol (delta9-THC) produces an activation of preproenkephalin (PENK) gene expression in the rat hypothalamus. The levels of circulating gonadal steroids concurrently modulate this neuropeptide in male and female rats. However, whether gonadal steroids regulate delta9-THC effects on PENK gene expression in the hypothalamus of male and female rats remains unknown. To test this hypothesis, experiments were carried out on intact, 2-week-gonadectomized, 1-week-gonadectomized, 1-week-dihydrotestosterone (DHT) replaced male rats, and 2-week-gonadectomized, 1-week-gonadectomized, 1-week-oestradiol replaced female rats. One week after hormonal replacement, animals were treated with vehicle or delta9-THC (5 mg/kg/day, i.p. 7 days). In males, delta9-THC administration to intact animals induced PENK mRNA in the paraventricular nucleus (PVN) and ventromedial nucleus (VMN) of the hypothalamus. Orchidectomy did not affect basal PENK mRNA levels in the PVN, but reduced PENK mRNA levels in the VMN. However, delta9-THC treatment induced PENK gene expression to the same extent in both hypothalamic nuclei of intact, castrated and DHT-replaced males. In females, ovariectomy decreased PENK gene expression in PVN and VMN. delta9-THC administration increased PENK gene expression in castrated females, but had no effect in the oestradiol-replaced group. Taken together, these results suggest gender differences in the response of chronic exposure to cannabinoids on PENK gene expression in the hypothalamus. Furthermore, it appears that alterations in opioid gene expression induced by cannabinoids in female rats depend upon the presence or absence of circulating oestradiol.
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Affiliation(s)
- Javier Corchero
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
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31
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Vasudevan N, Ogawa S, Pfaff D. Estrogen and thyroid hormone receptor interactions: physiological flexibility by molecular specificity. Physiol Rev 2002; 82:923-44. [PMID: 12270948 DOI: 10.1152/physrev.00014.2002] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The influence of thyroid hormone on estrogen actions has been demonstrated both in vivo and in vitro. In transient transfection assays, the effects of liganded thyroid hormone receptors (TR) on transcriptional facilitation by estrogens bound to estrogen receptors (ER) display specificity according to the following: 1) ER isoform, 2) TR isoform, 3) the promoter through which transcriptional facilitation occurs, and 4) cell type. Some of these molecular phenomena may be related to thyroid hormone signaling of seasonal limitations upon reproduction. The various combinations of these molecular interactions provide multiple and flexible opportunities for relations between two major hormonal systems important for neuroendocrine feedbacks and reproductive behaviors.
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Affiliation(s)
- Nandini Vasudevan
- Laboratory of Neurobiology and Behavior, The Rockefeller University, New York, New York 10021, USA
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32
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Acosta-Martinez M, Etgen AM. The role of delta-opioid receptors in estrogen facilitation of lordosis behavior. Behav Brain Res 2002; 136:93-102. [PMID: 12385794 DOI: 10.1016/s0166-4328(02)00103-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The present study investigated the role of delta-opioid receptors (ORs) in estrogen facilitation of female rat reproductive behavior (lordosis). Infusion of 2 microg of the selective delta-OR agonist [D-Pen(2),D-Pen(5)]-enkephalin (DPDPE), into the third ventricle facilitated lordosis behavior in ovariectomized (OVX) rats injected with estrogen (E) 48 and 24 h before behavioral testing. Pretreatment with the selective delta-OR antagonist naltrindole (NTDL) blocked DPDPE effects on lordosis behavior. Ventricular infusion of NTDL (40 microg) also suppressed lordosis behavior in fully receptive OVX rats primed with both E and progesterone (P). In addition, NTDL blocked lordosis behavior when infused into the ventromedial nucleus of the hypothalamus (VMH) but not into the medial preoptic area (mPOA). Site-specific infusion of DPDPE into the VMH had dose-dependent, dual effects on lordosis behavior. While a very low dose of DPDPE (0.01 microg) facilitated lordosis behavior, a higher dose (1.0 microg) inhibited receptivity in OVX rats primed with E and a low dose (50 microg) of P. We used 3H-DPDPE to measure the density of delta-ORs in OVX rats treated with vehicle or with E by receptor autoradiography. E treatment did not have any effect on the density of DPDPE binding sites in the VMH, mPOA, medial amygdala, or caudate putamen. The behavioral effects of the ligands used in this study suggest that activation of delta-OR in the VMH by endogenous opioids facilitates estrogen-dependent lordosis behavior.
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MESH Headings
- Analgesics, Opioid/pharmacology
- Animals
- Autoradiography
- Enkephalin, D-Penicillamine (2,5)-/pharmacology
- Estrogens/pharmacology
- Female
- Microinjections
- Naltrexone/analogs & derivatives
- Naltrexone/pharmacology
- Narcotic Antagonists/pharmacology
- Ovariectomy
- Posture
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/physiology
- Sexual Behavior, Animal/drug effects
- Stereotaxic Techniques
- Ventromedial Hypothalamic Nucleus/physiology
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Affiliation(s)
- Maricedes Acosta-Martinez
- Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Forchheimer 113, Bronx, NY 10461, USA.
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33
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Estrogen and aging affect the subcellular distribution of estrogen receptor-alpha in the hippocampus of female rats. J Neurosci 2002. [PMID: 11978836 DOI: 10.1523/jneurosci.22-09-03608.2002] [Citation(s) in RCA: 187] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Estrogen replacement increases both the number of dendritic spines and the density of axospinous synapses in the hippocampal CA1 region in young rats, yet this is attenuated in aged rats. The estrogen receptor-alpha (ER-alpha) is localized within select spines of CA1 pyramidal cells in young animals and thus may be involved locally in this process. The present study investigated the effects of estrogen on the ultrastructural distribution of ER-alpha in the CA1 of young (3-4 months) and aged (22-23 months) Sprague Dawley rats using postembedding immunogold electron microscopy. Within dendritic spines, most ER-alpha immunoreactivity (IR) was seen in plasmalemmal and cytoplasmic regions of spine heads, with a smaller proportion within 60 nm of the postsynaptic density. In presynaptic terminals, ER-alpha-IR was clustered and often associated with synaptic vesicles. Significant effects of both aging and estrogen were observed. Quantitative analysis revealed that nonsynaptic pools of ER-alpha-IR within the presynaptic and postsynaptic compartments were decreased (35 and 27%, respectively) in the young estrogen-replaced animals compared with those that received vehicle. Such localized regulation of ER-alpha in response to circulating estrogen levels might directly affect synaptic signaling in CA1 pyramidal cells. No estrogen treatment-related differences were observed in the aged animals. However, 50% fewer spines contained ER-alpha in the aged compared with young hippocampus. These data suggest that the decreased responsiveness of hippocampal synapses to estrogen in aged animals may result from age-related decrements in ER-alpha levels and its subcellular localization vis-à-vis the synapse. Such a role for spinous ER-alpha has important implications for age-related attenuation of estrogen-induced hippocampal plasticity.
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34
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Gore AC, Oung T, Woller MJ. Age-related changes in hypothalamic gonadotropin-releasing hormone and N-methyl-D-aspartate receptor gene expression, and their regulation by oestrogen, in the female rat. J Neuroendocrinol 2002; 14:300-9. [PMID: 11963827 DOI: 10.1046/j.1365-2826.2002.00777.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During reproductive ageing, the oestrous cycles of female rats become irregular and eventually cease. The mechanisms for reproductive senescence in rodents are believed to involve changes in hypothalamic neurones, including gonadotropin-releasing hormone (GnRH) cells and their afferent inputs. In addition, effects of oestrogen on hypothalamic function may vary in animals of different ages. These issues were addressed using young (aged 4-5 months), middle-aged (12-14 months) and old (24-26 months) female Sprague-Dawley rats. Animals were ovariectomized and given oestrogen or vehicle replacement. They were killed and the preoptic area-anterior hypothalamus (POA-AH) and the medial basal hypothalamus-median eminence (MBH-ME) were dissected out, RNA extracted, and RNase protection assay used to quantify gene expression of several hypothalamic molecules. In the first experiment, GnRH RNA levels were measured in the POA-AH. No effects of ageing or oestrogen were observed on GnRH gene expression. This finding suggests that ageing and oestrogen may affect GnRH release from neuroterminals independently of de novo biosynthesis, and that this may involve other neurones that affect GnRH neurosecretory function. In the second experiment, we investigated changes in N-methyl-D-aspartate (NMDA) receptor subunit mRNA levels. These receptors play an important regulatory role in mediating effects of glutamate on GnRH function, and are themselves regulated by oestrogen and ageing. NMDA receptor subunit (NR) 1, 2a and 2b mRNA levels were quantified in the POA-AH and MBH-ME, the sites of GnRH perikarya and neuroterminals, respectively. In general, oestrogen had inhibitory effects on NR1 and NR2a, and differential effects on NR2b subunit mRNA levels. NMDA receptor subunit mRNA levels also changed during ageing: age-related decreases in NR1 mRNA occurred in the MBH-ME, and an age-related increase in NR2b mRNA occurred in the POA-AH. Taken together, these results demonstrate subunit- and region-specific changes in hypothalamic NMDA receptor subunit gene expression with oestrogen and ageing. These alterations could have implications for the physiological effects of glutamate on its NMDA receptor, and impact the regulation of reproductive and other neuroendocrine and autonomic functions by hypothalamic glutamatergic inputs.
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Affiliation(s)
- A C Gore
- Kastor Neurobiology of Aging Laboratories, Fishberg Research Center for Neurobiology, Brookdale Department of Geriatrics and Adult Development, Mount Sinai School of Medicine, New York, NY, USA.
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35
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Krzanowska EK, Ogawa S, Pfaff DW, Bodnar RJ. Reversal of sex differences in morphine analgesia elicited from the ventrolateral periaqueductal gray in rats by neonatal hormone manipulations. Brain Res 2002; 929:1-9. [PMID: 11852025 DOI: 10.1016/s0006-8993(01)03350-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Male rats display significantly greater analgesic responses than female rats following systemic, ventricular and intracerebral morphine administration into either the ventrolateral periaqueductal gray (vlPAG) or the rostral ventromedial medulla, and following beta-endorphin administration into the vlPAG. Although adult gonadectomy severely reduces nonopioid forms of swim stress-induced analgesia, the marked sex differences in morphine analgesia were minimally affected by either male or female adult gonadectomy. Since very little is known about neonatal effects of gonadal hormones upon sex differences in morphine analgesia elicited from the vlPAG, the present study evaluated the effects of neonatal (within 1 day of birth) castration in male rat pups relative to sham-operated controls, and systemic androgenization with testosterone propionate in female rat pups relative to vehicle-injected controls upon baseline nociceptive thresholds and morphine analgesia elicited from the vlPAG in rats tested as adults. Significant sex differences in morphine analgesia elicited from the vlPAG were observed with adult males receiving neonatal sham surgeries displaying significantly greater morphine analgesia on two nociceptive measures than adult females tested during the estrous phase and receiving neonatal vehicle injections. Neonatal gonadectomy essentially reversed the pattern of sex difference effects upon morphine analgesia elicited from the vlPAG. Neonatally-castrated male rats tested in adulthood displayed dramatic reductions in morphine analgesia elicited from the vlPAG on both the tail-flick (approximately 15-fold rightward shift) and jump (6-fold rightward shift) tests relative to sham-operated males, and essentially mirrored those of vehicle-treated females. Conversely, neonatally-androgenized female rats tested in adulthood displayed dramatic increases in morphine analgesia elicited from the vlPAG on the tail-flick (5-fold leftward shift) and jump (12-fold leftward shift) tests relative to vehicle-treated females, and approximated those observed in sham-operated males. The potent differences between neonatally-castrated and sham-operated male rats and between neonatally-androgenized and vehicle-treated female rats suggest a possible 'organizational' role of gonadal hormones in mediating sex differences in morphine analgesia elicited from the vlPAG.
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Affiliation(s)
- Eliza K Krzanowska
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College and City University of New York, Flushing, NY 11367, USA
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36
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Vasudevan N, Zhu YS, Daniel S, Koibuchi N, Chin WW, Pfaff D. Crosstalk between oestrogen receptors and thyroid hormone receptor isoforms results in differential regulation of the preproenkephalin gene. J Neuroendocrinol 2001; 13:779-90. [PMID: 11578528 DOI: 10.1046/j.1365-2826.2001.00693.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Nuclear receptors are ligand-activated transcription factors, which have the potential to integrate internal metabolic events in an organism, with consequences for control of behaviour. Previous studies from this laboratory have shown that thyroid hormone receptor (TR) isoforms can inhibit oestrogen receptor (ER)alpha-mediated induction of preproenkephalin (PPE) gene expression in the hypothalamus. Also, thyroid hormone administration inhibits lordosis, a behaviour facilitated by PPE expression. We have examined the effect of multiple ligand-binding TR isoforms on the ER-mediated induction of the PPE gene in transient transfection assays in CV-1 cells. On a natural PPE gene promoter fragment containing two putative oestrogen response elements (EREs), both ER alpha and beta isoforms mediate a four to five-fold induction by oestrogen. Cotransfection of TR alpha 1 along with ER alpha inhibited the ER alpha transactivation of PPE by approximately 50%. However, cotransfection with either TR beta 1 or TR beta 2 expression plasmids produced no effect on the ER alpha or ER beta mediated induction of PPE. Therefore, under these experimental conditions, interactions with a single ER isoform are specific to an individual TR isoform. Transfection with a TR alpha 1 DNA-binding mutant could also inhibit ER alpha transactivation, suggesting that competition for binding on the ERE may not be the exclusive mechanism for inhibition. Data with the coactivator, SRC-1, suggested that coactivator squelching may participate in the inhibition. In dramatic contrast, when ER beta is cotransfected, TR alpha 1 stimulated ER beta-mediated transactivation of PPE by approximately eight-fold over control levels. This is the first study revealing specific interactions among nuclear receptor isoforms on a neuroendocrine promoter. These data also suggest that the combinatorics of ER and TR isoforms allow multiple forms of flexible gene regulations in the service of neuroendocrine integration.
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Affiliation(s)
- N Vasudevan
- Laboratory of Neurobiology and Behavior, Rockefeller University, New York, NY 10021, USA.
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37
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Adams MM, Oung T, Morrison JH, Gore AC. Length of postovariectomy interval and age, but not estrogen replacement, regulate N-methyl-D-aspartate receptor mRNA levels in the hippocampus of female rats. Exp Neurol 2001; 170:345-56. [PMID: 11476600 DOI: 10.1006/exnr.2001.7716] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Estrogens and N-methyl-D-aspartate (NMDA) receptors regulate multiple aspects of morphological and functional plasticity in young animals. For example, estrogens increase spine density in the hippocampus, and NMDA antagonists block these effects. Few studies have examined the effects of age, postovariectomy interval, and duration of estrogen replacement in the hippocampus and more specifically on NMDA receptor subunits. Therefore, the present study was designed to investigate the effects of short- and long-term estrogen replacement or deprivation on mRNA levels of three NMDA receptor subunits, NR1, NR2A, and NR2B, in the hippocampus of aging female Sprague-Dawley rats. Young (3- to 4-month-old) and middle-aged (12- to 13-month-old) rats were ovariectomized for 1 month and then treated with estrogen or vehicle for either 2 days or 2 weeks. Another set of middle-aged and aged (24-to 25-month-old) animals were ovariectomized for 6 months and treated with estrogen or vehicle for 2 days or 2 weeks. RNase protection assay was used to assess changes in the NMDA receptor subunit mRNA levels. Our results demonstrated significant effects of age and length of ovariectomy on NMDA receptor mRNA levels, with little effect of the estrogen status of the animals on these parameters. The largest effect was seen for the length of the postovariectomy interval, with the results demonstrating that rats with a short-term ovariectomy have substantially higher NMDA receptor subunit mRNA levels than animals with long-term ovariectomy. The most dramatic effects of aging were seen for NR1 and NR2B mRNAs in ventral hippocampus, with large age-related increases. These data suggest that age and duration of ovariectomy impact NMDA receptor mRNA levels in the hippocampus, potentially affecting the stoichiometry and/or function of these receptors. These findings have important implications for postmenopausal or hysterectomy/oophorectomy estrogen depletion and replacement in humans.
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Affiliation(s)
- M M Adams
- Kastor Neurobiology of Aging Laboratory, Mount Sinai School of Medicine, New York, New York 10029, USA
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38
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Zhu YS, Cai LQ, You X, Duan Y, Imperato-McGinley J, Chin WW, Pfaff DW. Molecular analysis of estrogen induction of preproenkephalin gene expression and its modulation by thyroid hormones. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2001; 91:23-33. [PMID: 11457489 DOI: 10.1016/s0169-328x(01)00109-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Estrogen receptors (ER) and thyroid hormone receptors (TR) are ligand-dependent nuclear transcription factors. Estrogen-induced preproenkephalin (PPE) gene expression in the hypothalamus is directly related to estrogen-induced lordosis behavior in the rat. In the present study, we showed that the PPE mRNA level in the ventromedial hypothalamus of female rats was significantly decreased by ovariectomy. This decrease was reversed by estrogen replacement in a dose- and time-dependent manner. Using transient transfection and electrophoretic mobility shift assays (EMSA), functional estrogen response elements (ERE) were identified between -437 and -145 base pairs (bp) of the rat PPE gene promoter region. Two ERE-like elements are present between -405 and -364 of the rat PPE gene promoter, which bind ERalpha as demonstrated by EMSA. Estrogen produced a dose-dependent increase in CAT activity in cotransfection assays with ERalpha expression vector and a 437PPE-CAT reporter construct containing 437 bp of the rat PPE gene promoter and the CAT reporter gene. This estrogen-induced PPE promoter activity was inhibited by liganded-TR in transient cotransfection assays. Analysis of DNA-protein interactions by EMSA revealed that both ERalpha and TR (alpha1 and beta1) could bind to the EREs in the rat PPE gene promoter. Furthermore, estrogen induction of PPE mRNA in the ventromedial hypothalamus of the ovariectomized female rat was significantly attenuated by concomitant administration of triiodothyronine. These results suggest that estrogen regulation of the hypothalamic PPE gene expression is mediated through an estrogen-receptor complex directly interacting with the functional EREs in its promoter region; and that this estrogen effect can be modified by thyroid hormones.
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Affiliation(s)
- Y S Zhu
- Laboratory of Neurobiology and Behavior, The Rockefeller University, New York, NY10021, USA.
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39
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Adams MM, Shah RA, Janssen WG, Morrison JH. Different modes of hippocampal plasticity in response to estrogen in young and aged female rats. Proc Natl Acad Sci U S A 2001; 98:8071-6. [PMID: 11427724 PMCID: PMC35469 DOI: 10.1073/pnas.141215898] [Citation(s) in RCA: 169] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2001] [Accepted: 05/02/2001] [Indexed: 11/18/2022] Open
Abstract
Estrogen regulates hippocampal dendritic spine density and synapse number in an N-methyl-D-aspartate (NMDA) receptor-dependent manner, and these effects may be of particular importance in the context of age-related changes in endocrine status. We investigated estrogen's effects on axospinous synapse density and the synaptic distribution of the NMDA receptor subunit, NR1, within the context of aging. Although estrogen induced an increase in axospinous synapse density in young animals, it did not alter the synaptic representation of NR1, in that the amount of NR1 per synapse was equivalent across groups. Estrogen replacement in aged female rats failed to increase axospinous synapse density; however, estrogen up-regulated synaptic NR1 compared with aged animals with no estrogen. Therefore, the young and aged hippocampi react differently to estrogen replacement, with the aged animals unable to mount a plasticity response generating additional synapses, yet responsive to estrogen with respect to additional NMDA receptor content per synapse. These findings have important implications for estrogen replacement therapy in the context of aging.
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Affiliation(s)
- M M Adams
- Kastor Neurobiology of Aging Laboratories, Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, New York, NY 10029, USA
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40
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Lee BJ, Cho GJ, Norgren RB, Junier MP, Hill DF, Tapia V, Costa ME, Ojeda SR. TTF-1, a homeodomain gene required for diencephalic morphogenesis, is postnatally expressed in the neuroendocrine brain in a developmentally regulated and cell-specific fashion. Mol Cell Neurosci 2001; 17:107-26. [PMID: 11161473 DOI: 10.1006/mcne.2000.0933] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
TTF-1 is a member of the Nkx family of homeodomain genes required for morphogenesis of the hypothalamus. Whether TTF-1, or other Nkx genes, contributes to regulating differentiated hypothalamic functions is not known. We now report that postnatal hypothalamic TTF-1 expression is developmentally regulated and associated with the neuroendocrine process of female sexual development. Lesions of the hypothalamus that cause sexual precocity transiently activate neuronal TTF-1 expression near the lesion site. In intact animals, hypothalamic TTF-1 mRNA content also increases transiently, preceding the initiation of puberty. Postnatal expression of the TTF-1 gene was limited to subsets of hypothalamic neurons, including LHRH neurons, which control sexual maturation, and preproenkephalinergic neurons of the lateroventromedial nucleus of the basal hypothalamus, which restrain sexual maturation and facilitate reproductive behavior. TTF-1 mRNA was also detected in astrocytes of the median eminence and ependymal/subependymal cells of the third ventricle, where it colocalized with erbB-2, a receptor involved in facilitating sexual development. TTF-1 binds to and transactivates the erbB-2 and LHRH promoters, but represses transcription of the preproenkephalin gene. The singular increase in hypothalamic TTF-1 gene expression that precedes the initiation of puberty, its highly specific pattern of cellular expression, and its transcriptional actions on genes directly involved in neuroendocrine reproductive regulation suggest that TTF-1 may represent one of the controlling factors that set in motion early events underlying the central activation of mammalian puberty.
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Affiliation(s)
- B J Lee
- Division of Neuroscience, Oregon Regional Primate Research Center/Oregon Health Sciences University, Beaverton, Oregon 97006, USA
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41
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Commons KG, Pfaff DW. Ultrastructural evidence for enkephalin mediated disinhibition in the ventromedial nucleus of the hypothalamus. J Chem Neuroanat 2001; 21:53-62. [PMID: 11173220 DOI: 10.1016/s0891-0618(00)00093-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The ventromedial nucleus of the hypothalamus (VMN) regulates the estrogen-dependent appearance of female mating behavior, lordosis. Accumulating evidence suggests that estrogen might exert its control over lordosis by acting, in part, on neurons that contain enkephalin in the VMN. The expression of the enkephalin precursor gene is robustly stimulated by estrogen and is correlated with the later appearance of lordosis. GABA has also been implicated as an important neurotransmitter for the appearance of lordosis. Because enkephalin is thought to act in several brain areas to modulate the activity of GABAergic neurons, we studied the ultrastructural morphology and relationship between neurons containing these neurochemicals using dual-labeling immunocytochemistry in ovariectornized rats, half of which received estrogen replacement. Immunolabeling for enkephalin was almost always detected within axon terminals (695 axonal profiles sampled), while GABA immunoreactivity was more often localized to cell bodies and dendrites (191 profiles), than to axons (63 profiles). Axon terminals containing enkephalin immunolabeling provided a major innervation to soma or dendrites containing GABA. That is, over one third (94/245) of the axon terminals in contact with GABA-immunoreactive dendrites contained enkephalin. Furthermore, these GABA-immunoreactive dendrites accounted for a fifth of the somatodendritic processes associated with enkephalin-containing axon terminals. These findings support the hypothesis that enkephalin may act in the VMN by inhibiting GABAergic neurons, which could result in the disinhibition of neural circuits relevant for lordosis.
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Affiliation(s)
- K G Commons
- Laboratory of Neurobiology and Behavior, The Rockefeller University, 1230 York Avenue, Box 275, New York, NY 10012, USA.
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42
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Krebs CJ, Jarvis ED, Chan J, Lydon JP, Ogawa S, Pfaff DW. A membrane-associated progesterone-binding protein, 25-Dx, is regulated by progesterone in brain regions involved in female reproductive behaviors. Proc Natl Acad Sci U S A 2000; 97:12816-21. [PMID: 11070092 PMCID: PMC18847 DOI: 10.1073/pnas.97.23.12816] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ventromedial hypothalamus (VMH) plays a central role in the regulation of the female reproductive behavior lordosis, a behavior dependent upon the sequential activation of receptors for the ovarian steroid hormones estradiol (E) and progesterone (P). These receptors function as transcription factors to alter the expression of target genes. To discover behaviorally relevant genes targeted by E and P in the VMH, we used the differential display PCR to identify messenger RNAs that are differentially expressed in the hypothalamus of ovariectomized (ovx) rats treated with E alone compared with ovariectomized rats treated with E and P. We show here that one interesting mRNA within the hypothalamus that is repressed by P after E priming encodes the protein 25-Dx, the rat homolog of the human membrane-associated P-binding protein Hpr6.6. Neurons in the brain containing the highest levels of 25-Dx are located in several nuclei of the basal forebrain, including the VMH. 25-Dx expression is also higher in the hypothalamus of female P receptor "knockout" mice than in their wild-type littermates. These findings suggest a mechanism in which the activation of nuclear P receptor represses expression of a membrane P receptor, 25-Dx, during lordosis facilitation.
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Affiliation(s)
- C J Krebs
- Laboratory of Neurobiology and Behavior and Laboratory of Animal Behavior, The Rockefeller University, New York, NY 10021, USA.
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43
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Quiñones-Jenab V, Perrotti LI, Mc Monagle J, Ho A, Kreek MJ. Ovarian hormone replacement affects cocaine-induced behaviors in ovariectomized female rats. Pharmacol Biochem Behav 2000; 67:417-22. [PMID: 11164068 DOI: 10.1016/s0091-3057(00)00381-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To determine whether cocaine-induced behavioral alterations are modulated by ovarian hormones, ovariectomized rats were randomly assigned to one of two drug treatment conditions: "binge" cocaine (three 15-mg/kg intraperitoneal (ip) injections, 1 h apart) or saline administration; and four hormone pretreatment sub-groups: vehicle control, estrogen, progesterone, or estrogen+progesterone. Cocaine-treated animals displayed more locomotor activity than saline-treated animals and locomotor activity was higher after the third injection than after the first two injections. When analyzed according to hormone group, the administration of estrogen+progestrone suppressed cocaine-induced locomotion after the first injection; this effect was significant when compared to estrogen-pretreated animals. While in each condition cocaine-treated animals displayed significantly higher stereotypic activity than saline-treated animals, in the estrogen+progesterone replacement group, there was more activity after the second injection of cocaine than after the first. Interestingly, animals in the estrogen+progesterone group had significantly lower plasma levels of the cocaine metabolite, benzoylecgonine, than animals in the progesterone or estrogen groups. These results extend our earlier findings in the intact female rat, which suggest an interaction between the endocrine environment, cocaine metabolism, and cocaine-induced behaviors. These effects may underlie reported sex and estrous cycle differences in cocaine-induced behavioral activity.
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Affiliation(s)
- V Quiñones-Jenab
- The Laboratory of the Biology of Addictive Disease, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
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Quiñones-Jenab V, Perrotti LI, Ho A, Jenab S, Schlussman SD, Franck J, Kreek MJ. Cocaine affects progesterone plasma levels in female rats. Pharmacol Biochem Behav 2000; 66:449-53. [PMID: 10880704 DOI: 10.1016/s0091-3057(00)00213-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Female Fischer rats injected with cocaine in a "binge" pattern (15 mg/kg, IP, three times a day, at 1-h intervals) for 1 day had significantly higher levels of progesterone than saline-treated controls (p < 0.001). When analyzed by the stage of the estrous cycle, animals in proestrus showed significantly higher cocaine-induced progesterone plasma levels than those in other stages of the cycle (p < 0.01). Progesterone plasma levels were also increased after a single dose of cocaine (15 mg/kg). However, 3 h postinjection progesterone plasma levels had returned to normal. Thus, cocaine modulation of progesterone plasma levels appears to be an acute effect. In ovariectomized rats pretreated with estrogen, progesterone, or estrogen + progesterone, no significant differences were observed in progesterone plasma levels after acute "binge" pattern cocaine administration. Thus, acute cocaine induced increases in progesterone plasma levels in intact female rats are probably due to an increase in secretion rates of progesterone rather than an acceleration of its biotransformation. Due to the profound effects of progesterone in the modulation of CNS plasticity, the modulation of progesterone plasma level by cocaine may have implications for reproductive processes and neuronal functions of women. Moreover, cocaine may affect the progesterone levels in women utilizing progesterone-based contraception or steroid replacement treatment after menopause.
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Krzanowska EK, Znamensky V, Wilk S, Bodnar RJ. Antinociceptive and behavioral activation responses elicited by d-Pro(2)-endomorphin-2 in the ventrolateral periaqueductal gray are sensitive to sex and gonadectomy differences in rats. Peptides 2000; 21:705-15. [PMID: 10876054 DOI: 10.1016/s0196-9781(00)00191-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Sex differences have been observed in antinociception after morphine administered into either the lateral ventricles, rostral ventromedial medulla, or ventrolateral periaqueductal gray such that male rats exhibit significantly greater antinociception than female rats. Adult gonadectomy produced small, but significant changes in morphine antinociception relative to same-sex sham-operated controls. The present study examined whether sex and adult gonadectomy differences were observed in antinociceptive responses after D-Pro(2)-Endomorphin-2 (1-50 microg) elicited from the ventrolateral periaqueductal gray (vlPAG) on the tail-flick and jump tests in rats, and compared these effects with morphine antinociception. D-Pro(2)-Endomorphin-2 antinociception in the vlPAG was significantly greater in estrous-phase, sham-operated and ovariectomized female rats relative to sham-operated and castrated male rats on the tail-flick, but not jump test that differed markedly from the greater magnitude of morphine antinociception noted for male rats on both tests. In testing whether D-Pro(2)-Endomorphin-2's antinociceptive sex differences were secondary to alterations in activity, similar decreases in the pattern of total activity were observed after D-Pro(2)-Endomorphin-2 in the vlPAG in male and female rats. In evaluating whether male and female rats differed in their behavioral activation responses after D-Pro(2)-Endomorphin-2 in the vlPAG, significantly more excessive grooming, seizures, barrel rolls and explosive running behaviors were observed after D-Pro(2)-Endomorphin-2 in male, but not female rats during the precise periods of time when they were failing to display robust antinociceptive responses on the tail-flick test. Thus, the different patterns of sex differences after D-Pro(2)-Endomorphin-2 in the vlPAG appear to be attributable to sex-dependent alterations in behavioral activation rather than nociceptive processing per se.
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Affiliation(s)
- E K Krzanowska
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, CUNY, 65-30 Kissena Blvd., 11367, Flushing, NY 11367, USA
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Amandusson A, Hallbeck M, Hallbeck AL, Hermanson O, Blomqvist A. Estrogen-induced alterations of spinal cord enkephalin gene expression. Pain 1999; 83:243-8. [PMID: 10534596 DOI: 10.1016/s0304-3959(99)00109-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Enkephalin-synthesizing neurons in the superficial laminae of the spinal and trigeminal dorsal horn are critical components of the endogenous pain-modulatory system. We have previously demonstrated that these neurons display intracellular estrogen receptors, suggesting that estrogen can potentially influence their enkephalin expression. By using Northern blot, we now show that a bolus injection of estrogen results in a rapid increase in spinal cord enkephalin mRNA levels in ovariectomized female rats. Thus, 4 h after estrogen administration the enkephalin mRNA-expression in the lumbar spinal cord was on average 68% higher (P<0.05) than in control animals injected with vehicle only. A small increase in the amount of enkephalin mRNA was also seen after 8 h (P<0.05), whereas no difference between estrogen-injected and control animals was found after 24 h or at time periods shorter than 4 h. Taken together with the previous anatomical data, the present findings imply that estrogen has an acute effect on spinal opioid levels in areas involved in the transmission of nociceptive information.
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Affiliation(s)
- A Amandusson
- Division of Cell Biology, Department of Biomedicine and Surgery, Faculty of Health Sciences, University of Linköping, S-581 85, Linköping, Sweden
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Murphy AZ, Shupnik MA, Hoffman GE. Androgen and estrogen (alpha) receptor distribution in the periaqueductal gray of the male Rat. Horm Behav 1999; 36:98-108. [PMID: 10506534 DOI: 10.1006/hbeh.1999.1528] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The midbrain periaqueductal gray (PAG) has been strongly implicated in numerous behaviors heavily influenced by the gonadal steroids estrogen and testosterone, including reproductive behavior, autonomic regulation, and antinociception. However, the location of receptors for these steroids within the PAG has not been carefully characterized. Immunocytochemical techniques were used to map the distribution of neurons immunoreactive for the androgen (AR) and estrogen receptor (alpha subtype; ERalpha) along the rostrocaudal axis of the PAG in the male rat. The results show that the PAG contains a large population of both androgen and estrogen receptor containing neurons. Neurons immunoreactive for either receptor were concentrated within the caudal two-thirds of the PAG. At midlevels of the PAG, ERalpha and AR immunoreactive neurons were located primarily within the dorsomedial and lateral PAG. In the caudal third of the PAG, immunoreactive cells were distributed primarily within the dorsal half. The distributions of ERalpha and AR were remarkably similar, and it is likely that some PAG neurons contain receptors for both gonadal steroids, similar to what has been previously reported for the male rat hypothalamus. The results of this study suggest that the PAG may provide the anatomical substrate for steroid mediated changes in nociceptive thresholds and reproductive behavior.
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Affiliation(s)
- A Z Murphy
- Baltimore School of Medicine, University of Maryland, 685 W. Baltimore Street, Baltimore, Maryland, 21201, USA
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Dellovade TL, Kia HK, Zhu YS, Pfaff DW. Thyroid hormone coadministration inhibits the estrogen-stimulated elevation of preproenkephalin mRNA in female rat hypothalamic neurons. Neuroendocrinology 1999; 70:168-74. [PMID: 10516479 DOI: 10.1159/000054473] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Expression of the enkephalin gene in ventromedial hypothalamus (VMH) of the female rat has been correlated with the performance of lordosis behavior. By antisense DNA evidence, it has been drawn into a causal role as well. Here, we explored whether, parallel to earlier molecular and behavioral results, thyroid hormone coadministration could disrupt the estrogenic induction of preproenkephalin (PPE) mRNA. As expected, estradiol benzoate treatment to ovariectomized rats led to a large and significant increase in PPE gene expression in the VMH. This increase was inhibited by coadministration of thyroid hormone. The thyroid hormone interference in PPE gene expression was specific to the VMH, as there were no significant effects in the central nucleus of the amygdala or in the caudate/putamen. These in situ hybridization histochemical results form a direct parallel both to previous transcriptional measurements and to reproductive behavior assays in which thyroid hormones were able to oppose estrogenic facilitation. Previous evidence supports the notion of competitive DNA binding and protein/protein interactions providing mechanisms for nuclear thyroid hormone receptors to affect estrogen receptor function, but other, additional mechanisms cannot be ruled out. To date, both oxytocin and PPE gene expression represent potential hypothalamic systems by which thyroid hormones could interfere with estrogen-stimulated female rat reproductive behavior.
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Affiliation(s)
- T L Dellovade
- Laboratory of Neurobiology and Behavior, The Rockefeller University, New York, N.Y., USA
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Pfaff DW, Ogawa S, Kow LM. Neural oxytocinergic systems as genomic targets for hormones and as modulators of hormone-dependent behaviors. Results Probl Cell Differ 1999; 26:91-105. [PMID: 10453461 DOI: 10.1007/978-3-540-49421-8_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
At the molecular level, estradiol turns on the gene for oxytocin in a subset of paraventricular hypothalamic neurons and turns on the gene for the oxytocin receptor in other limbic and hypothalamic cell groups. As a result, oxytocin deposition, whose signal is transduced both through G alpha (q/11) and Gi to stimulate phosphatidylinositol turnover, facilitates electrical activity in certain hypothalamic neurons. Consequently, affiliative behaviors including those closely associated with reproduction--mating behaviors and parental behaviors--are promoted. One important aspect of this effect is the preservation of instinctive behaviors associated with reproduction, in the face of disturbances due to mild stress.
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Affiliation(s)
- D W Pfaff
- Rockefeller University, New York, NY 10021, USA
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Quiñones-Jenab V, Ho A, Schlussman SD, Franck J, Kreek MJ. Estrous cycle differences in cocaine-induced stereotypic and locomotor behaviors in Fischer rats. Behav Brain Res 1999; 101:15-20. [PMID: 10342395 DOI: 10.1016/s0166-4328(98)00073-4] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
This study was conducted to characterize female behavioral response to acute 'binge' pattern cocaine administration (15 mg kg(-1) i.p., three times a day, at 1 h intervals) during the different stages of the estrous cycle in Fischer rats. Cocaine administration significantly increased stereotypic behavior and locomotion in females. Animals in estrus showed significantly higher cocaine-induced stereotypic and locomotive behavioral responses than those in other stages of the cycle. Plasma levels of the cocaine metabolite benzoylecgonine during metestrus diestrus were significantly higher than during estrus and proestrus probably reflecting more rapid biotransformation of cocaine. Therefore, it is likely that the hormonal fluctuations associated with the estrous cycle modulate both cocaine metabolism and the behavioral responses to cocaine in female rats. This in turn may have important implications in gender differences in behavioral responses to cocaine.
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Affiliation(s)
- V Quiñones-Jenab
- The Laboratory of the Biology of Addictive Disease, The Rockefeller University, NY, NY 10021, USA.
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